Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 232 insertions, 0 deletions

diff --git a/qobject/qjson.c b/qobject/qjson.c
new file mode 100644
index 000000000..167fcb429
--- /dev/null
+++ b/qobject/qjson.c
@@ -0,0 +1,232 @@
+/*
+ * QObject JSON integration
+ *
+ * Copyright IBM, Corp. 2009
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qapi/qmp/json-parser.h"
+#include "qapi/qmp/json-writer.h"
+#include "qapi/qmp/qjson.h"
+#include "qapi/qmp/qbool.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qmp/qlist.h"
+#include "qapi/qmp/qnum.h"
+#include "qapi/qmp/qstring.h"
+
+typedef struct JSONParsingState {
+    JSONMessageParser parser;
+    QObject *result;
+    Error *err;
+} JSONParsingState;
+
+static void consume_json(void *opaque, QObject *json, Error *err)
+{
+    JSONParsingState *s = opaque;
+
+    assert(!json != !err);
+    assert(!s->result || !s->err);
+
+    if (s->result) {
+        qobject_unref(s->result);
+        s->result = NULL;
+        error_setg(&s->err, "Expecting at most one JSON value");
+    }
+    if (s->err) {
+        qobject_unref(json);
+        error_free(err);
+        return;
+    }
+    s->result = json;
+    s->err = err;
+}
+
+/*
+ * Parse @string as JSON value.
+ * If @ap is non-null, interpolate %-escapes.
+ * Takes ownership of %p arguments.
+ * On success, return the JSON value.
+ * On failure, store an error through @errp and return NULL.
+ * Ownership of %p arguments becomes indeterminate then.  To avoid
+ * leaks, callers passing %p must terminate on error, e.g. by passing
+ * &error_abort.
+ */
+static QObject *qobject_from_jsonv(const char *string, va_list *ap,
+                                   Error **errp)
+{
+    JSONParsingState state = {};
+
+    json_message_parser_init(&state.parser, consume_json, &state, ap);
+    json_message_parser_feed(&state.parser, string, strlen(string));
+    json_message_parser_flush(&state.parser);
+    json_message_parser_destroy(&state.parser);
+
+    if (!state.result && !state.err) {
+        error_setg(&state.err, "Expecting a JSON value");
+    }
+
+    error_propagate(errp, state.err);
+    return state.result;
+}
+
+QObject *qobject_from_json(const char *string, Error **errp)
+{
+    return qobject_from_jsonv(string, NULL, errp);
+}
+
+/*
+ * Parse @string as JSON value with %-escapes interpolated.
+ * Abort on error.  Do not use with untrusted @string.
+ * Return the resulting QObject.  It is never null.
+ */
+QObject *qobject_from_vjsonf_nofail(const char *string, va_list ap)
+{
+    va_list ap_copy;
+    QObject *obj;
+
+    /* va_copy() is needed when va_list is an array type */
+    va_copy(ap_copy, ap);
+    obj = qobject_from_jsonv(string, &ap_copy, &error_abort);
+    va_end(ap_copy);
+
+    assert(obj);
+    return obj;
+}
+
+/*
+ * Parse @string as JSON value with %-escapes interpolated.
+ * Abort on error.  Do not use with untrusted @string.
+ * Return the resulting QObject.  It is never null.
+ */
+QObject *qobject_from_jsonf_nofail(const char *string, ...)
+{
+    QObject *obj;
+    va_list ap;
+
+    va_start(ap, string);
+    obj = qobject_from_vjsonf_nofail(string, ap);
+    va_end(ap);
+
+    return obj;
+}
+
+/*
+ * Parse @string as JSON object with %-escapes interpolated.
+ * Abort on error.  Do not use with untrusted @string.
+ * Return the resulting QDict.  It is never null.
+ */
+QDict *qdict_from_vjsonf_nofail(const char *string, va_list ap)
+{
+    QDict *qdict;
+
+    qdict = qobject_to(QDict, qobject_from_vjsonf_nofail(string, ap));
+    assert(qdict);
+    return qdict;
+}
+
+/*
+ * Parse @string as JSON object with %-escapes interpolated.
+ * Abort on error.  Do not use with untrusted @string.
+ * Return the resulting QDict.  It is never null.
+ */
+QDict *qdict_from_jsonf_nofail(const char *string, ...)
+{
+    QDict *qdict;
+    va_list ap;
+
+    va_start(ap, string);
+    qdict = qdict_from_vjsonf_nofail(string, ap);
+    va_end(ap);
+    return qdict;
+}
+
+static void to_json(JSONWriter *writer, const char *name,
+                    const QObject *obj)
+{
+    switch (qobject_type(obj)) {
+    case QTYPE_QNULL:
+        json_writer_null(writer, name);
+        break;
+    case QTYPE_QNUM: {
+        QNum *val = qobject_to(QNum, obj);
+
+        switch (val->kind) {
+        case QNUM_I64:
+            json_writer_int64(writer, name, val->u.i64);
+            break;
+        case QNUM_U64:
+            json_writer_uint64(writer, name, val->u.u64);
+            break;
+        case QNUM_DOUBLE:
+            json_writer_double(writer, name, val->u.dbl);
+            break;
+        default:
+            abort();
+        }
+        break;
+    }
+    case QTYPE_QSTRING: {
+        QString *val = qobject_to(QString, obj);
+
+        json_writer_str(writer, name, qstring_get_str(val));
+        break;
+    }
+    case QTYPE_QDICT: {
+        QDict *val = qobject_to(QDict, obj);
+        const QDictEntry *entry;
+
+        json_writer_start_object(writer, name);
+
+        for (entry = qdict_first(val);
+             entry;
+             entry = qdict_next(val, entry)) {
+            to_json(writer, qdict_entry_key(entry), qdict_entry_value(entry));
+        }
+
+        json_writer_end_object(writer);
+        break;
+    }
+    case QTYPE_QLIST: {
+        QList *val = qobject_to(QList, obj);
+        QListEntry *entry;
+
+        json_writer_start_array(writer, name);
+
+        QLIST_FOREACH_ENTRY(val, entry) {
+            to_json(writer, NULL, qlist_entry_obj(entry));
+        }
+
+        json_writer_end_array(writer);
+        break;
+    }
+    case QTYPE_QBOOL: {
+        QBool *val = qobject_to(QBool, obj);
+
+        json_writer_bool(writer, name, qbool_get_bool(val));
+        break;
+    }
+    default:
+        abort();
+    }
+}
+
+GString *qobject_to_json_pretty(const QObject *obj, bool pretty)
+{
+    JSONWriter *writer = json_writer_new(pretty);
+
+    to_json(writer, NULL, obj);
+    return json_writer_get_and_free(writer);
+}
+
+GString *qobject_to_json(const QObject *obj)
+{
+    return qobject_to_json_pretty(obj, false);
+}